1. Field of the Invention
The present invention generally relates to information recording, and more particularly to information recording on recording media on which recording is performable.
2. Description of the Related Art
Recently, personal computers have been enabled to process AV (audio-visual) information such as music and images with the improvement of their performance. Since the AV information is very large in amount, DVD (digital versatile disk)-type optical disks have attracted attention. As the DVD-type optical disks have become less expensive, optical disk units as information recording apparatuses have been widely used as one type of a peripheral device for personal computers. The DVD-type optical disks include DVD-ROM, DVD-RAM, DVD-R (DVD-recordable), DVD-RW (DVD-rewritable), DVD+R (DVD+recordable), and DVD+RW (DVD+rewritable) disks, on which data is recorded based on their respective predetermined standards. The DVD+R and DVD+RW disks, for instance, which are similar to the DVD-ROM disks in physical properties, have excellent compatibility with a DVD-ROM drive.
For a DVD+R, it is possible to employ a recording method called “multi-session layout” by which the DVD+R is divided into a plurality of recording divisions (sessions) to be recorded with information. In the case of employing the multi-session layout for a DVD+R, the first session is opened after an inner drive area including a TOC (table of contents) zone, and is followed by a plurality of sessions. After the last session, an outer drive area is generated. Each session is composed of an intro (a lead-in in the case of the first session), data, and a closure (a lead-out in the case of the last session). Data is recorded on a DVD+R in recording units called “fragments.” The session is a region composed of at least one fragment to which predetermined information (a lead-in and a lead-out, for instance) is written. In recordable disks such as DVD+Rs, normally, data is sequentially recorded from the center to the periphery of the disk.